This invention relates to the field of cassette-like devices containing photosensitive film for use in connection with industrial cameras.
In accordance with a first prior art approach, a cassette is provided containing a roll of photosensitive media. The film is driven from the cassette by a pair of rollers external to the cassette and within the camera. One problem with this type of approach is that the lead end becomes fogged when the cassette is removed from the industrial camera since the lead end must always be present external of the cassette. Should this not occur, it would be impossible to drive the photosensitive media out of the cassette by means of the external rollers upon subsequent use of the cassette.
Another approach is to provide a pair of rollers within the cassette which are capable of eliminating the above-mentioned problem of fogging as the leader may be driven totally within the cassette and thereafter driven out again. This approach, however, is costly since the rollers, being inside the cassette, are thrown out when the cassette is disposed of upon the exhaustion of the photosensitive media therein.
Furthermore, through the use of both of these approaches, it is possible that the film may be driven by error all the way into the cassette (in the second approach beyond the "bite" of the roller pair) so that the media cannot be thereafter driven out of the cassette to thereby waste the remaining material therein.
It is thus highly desirable to provide a replaceable cassette-like supply device wherein the roller portion associated therewith is preserved for use with subsequent disposable cassettes in the interest of economy and the material is not fogged due to the elimination of the extended lead edge.